Dust collection system for compound miter saw

ABSTRACT

A dust or chip collection and diversion system is provided for a device having a cutting tool for performing a working operation on a workpiece. The position and orientation of the dust-receiving or dust-collecting opening remains constant with respect to the cutting tool regardless of the position or configuration of the device, the device having a movable blade or other cutting tool, thus greatly enhancing the dust collection effectiveness in any of a number of operational configurations. Such position and orientation of the dust-receiving opening is also independent of the movement or position of any adjustable or movable guard or workpiece-supporting fence.

This is a continuation of U.S. patent application Ser. No. 09/163,896filed Oct. 1, 1998 (pending), which is a continuation of applicationSer. No. 08/600,907 filed Feb. 13, 1996, now U.S. Pat. No. 5,819,619,which is a continuation of application Ser. No. 08/329,766 filed Oct.27, 1994 (now abandoned), which is a continuation of application Ser.No. 08/088,266 filed Jul. 7, 1993 (now abandoned), which is acontinuation of application Ser. No. 07/774,767 filed Oct. 9, 1991 (nowabandoned).

BACKGROUND AND SUMMARY OF THE INVENTION

The present invention relates generally to dust or chip collectionsystems for saws or other power operated equipment or machinery. Moreparticularly, the invention relates to such dust or chip collectionsystems with the dust collector being disposed on a movable portion ofthe saw or other such equipment in order to maintain properdust-collecting alignment with a movable saw blade or otherwork-performing device while performing various operations on aworkpiece.

Saws and other apparatuses designed for cutting or performing otherworking operations on a workpiece frequently require a saw blade,cutter, or other such work-performing device that is movable to a numberof different positions or orientations for performing variousoperations. Examples of such equipment include compound miter saws,which allow the user to selectively move the saw blade into any of anumber or positions or modes for square cutting, for miter cutting, forbevel cutting, or for compound cutting where a combination miter andbevel are cut. In addition, some operations, such as shaping or dadocutting operations, for example, require the use of saw blades or othercutting devices of different shapes or sizes to be substituted for oneanother in order to perform the desired operation on the workpiece,whether the workpiece is composed of wood, plastic, metal, or othermaterials. In most examples of such equipment, it is highly desirable toprovide a dust collection system for diverting dust and chips away fromthe user.

In order to accommodate these widely varied working operations, dustcollection ducts, or openings are frequently disposed on an adjustableguard so as to be at least partially adjustable for various operations,or on a fence in order to accommodate the varied positions ororientations of the blade or other cutter. If such dust collectoradjustability, by way of adjustment of the guard, were not provided, asubstantial loss of dust-collecting effectiveness would result, or avery large dust collection opening would have to be provided in order toaccommodate the widely varying range of movement, position, or size ofthe saw blade, cutter, or other working device. Such collection ducts oropenings on guards or fences have been found to be relativelyineffective in many of their adjusted positions, and such largecollection openings have been found to be cumbersome and disadvantageousbecause of the space occupied by them.

In an attempt to address the above-discussed problems, a variety ofother dust collection arrangements have previously been provided.However, many of such prior arrangements have suffered the same or otherdisadvantages, including difficulty in maintaining proper alignmentbetween the dust collection duct or opening and the saw blade or othercutter, inconvenience and interference when performing operations onlarge or odd-shaped workpieces, the possibility of inadvertentlymisplacing separate dust collection components, lack of adequate dustcollection, or other similar short-comings. Thus, the need has arisenfor a dust collection system for compound miter saws, or other powerequipment with movable or adjustable blades or cutters, which overcomesthese disadvantages, as well as providing greater dust-collectioneffectiveness, improved ease of operation, economy in manufacturing, andother advantages that will become readily apparent to those skilled inthe art from the discussion below.

In accordance with the present invention, an improved dust collectionsystem for a saw or other device having a movable blade or cutting toolis provided. The dust collection system is spaced away from the sawblade or other cutting tool, is separate from any blade or cutter guard,and includes a dust-receiving opening that is at a fixed locationrelative to the movable blade or cutting tool and movable therewith.Preferably, the dust-receiving opening has an orientation relative tothe blade or cutting tool that is aligned with a line that extendsbetween the opening and the blade or cutting tool, with such lineextending along a tangent to the rotation of the blade or cutting tool,and with such tangent preferably being at a location on the blade orcutting tool that engages the workpiece when the blade or cutting toolis moved to a workpiece-engaging position. Such dust collection openingorientation thus remains essentially constant during movement of theblade or cutting tool and is independent of any adjustment of the guard.

In preferred embodiments of the present invention for compound mitersaws, for example, the dust-receiving opening is disposed at the openend of a dust duct that is interconnected with a pivot mechanism that isadapted for pivotally moving the saw blade into and out of engagementwith a workpiece and for pivotally moving the saw blade among variouscutting configurations. Such preferred dust duct is pivotally movablewith a pivot arm and is preferably disposed in a bifurcated portion ofthe pivot arm in a space between a pair of spaced-apart legs. The dustduct is adapted for conveying dust or chips away from the saw and theuser and can be connected in dust-conveying communication with a dustcollection receptacle, either with or without powered dust extraction ordust-conveying vacuum equipment.

Additional objects, advantages, and features of the present inventionwill become apparent from the following description and the appendedclaims, taken in conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a front perspective view of an exemplary compound miter sawfeaturing a dust collection system according to the present invention.

FIG. 2 is a front elevational view of the compound miter saw of FIG. 1.

FIG. 3 is a rear elevational view of the compound miter saw of FIGS. 1and 2.

FIG. 4 is a left end elevational view of the compound miter saw of FIGS.1 through 3, with portions cut away to illustrate the dust-receivingduct of the present invention.

FIG. 5 is a schematic elevational view, diagrammatically illustratingthe exemplary compound miter saw in use for cutting a relatively thickworkpiece.

FIG. 6 is a schematic top plan view, diagrammatically illustrating theexemplary compound miter saw in use for performing a miter-cuttingoperation.

FIG. 7 is a schematic elevational view, similar to that of FIG. 6, butdiagrammatically illustrating a bevel-cutting operation.

FIG. 8 is an elevational view illustrating the optional inclusion of adust is collection receptacle in the exemplary dust collection system ofthe present invention.

FIG. 9 is a cross-sectional detail view of a preferred dust collectionduct according to the invention.

FIG. 10 is a top detail view of a preferred dust collection ductaccording to the invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

FIGS. 1 through 10 illustrate an exemplary compound miter saw having adust collection system according to the present invention, shown merelyfor purposes of illustration. One skilled in the art will readilyrecognize from the following description, taken in conjunction with theaccompanying drawings and claims, that the principles of the inventionare equally applicable to compound miter saws or other saws of typesother than that shown for purposes of illustration in the drawings.Similarly, one skilled in the art will readily recognize that theprinciples of a dust collection system according to the invention arealso applicable to other types of powered, or even unpowered, equipmentfor performing an operation on a workpiece. Such other types ofequipment include so-called “chop” saws, dado saws, spindle shapers,spindle sanders, or other types of powered or unpowered devices thatrequire movable blades or cutters in order or to perform variousdifferent workpiece working operations.

Referring primarily to FIGS. 1 through 4, an exemplary compound mitersaw 10 typically has a base assembly 12, including a table assembly 13,which is preferably rotatable in order to accommodate the variouscutting modes discussed below. The saw 10 also includes a saw blade 14,at least partially enclosed by a blade guard 16 and driven by a motor17, and a handle 18, which allows the operator to move the saw blade 14and the blade guard 16 from a clear position free of a workpiece 11(FIG. 4) to a cutting position with the saw blade 14 in cuttingengagement with the workpiece 11.

As is conventional in this type of equipment, a fence assembly,indicated generally by reference numeral 20, is interconnected with thebase assembly 12 and extends laterally across the table assembly 13,against which the workpiece 11 is positioned and supported forperforming a cutting operation thereon. The illustrated fence assembly20 includes a fixed fence portion 22 and a movable fence portion 24,with the fixed and movable fence portions 22 and 24, respectively,extending in a mutually aligned lateral direction, and with the movablefence portion 24 being laterally spaced away from the fixed fenceportion 22. Such lateral spacing or gap between the fixed and movablefence portions 22 and 24, respectively, provides clearance for the sawblade to perform a cutting operation completely through the workpiece11, regardless of the mode or type of cutting operation being performed.As is discussed in more detail below, the movable fence portion 24 islaterally movable toward and away from the fixed fence portion 22 inorder to allow the operator to selectively adjust the clearance gaptherebetween and thus accommodate the particular cutting operation beingperformed.

As is typical in this type of equipment, the compound miter saw 10depicted in the drawings is capable of a number of different cuttingmodes or positions. Such positions include those forstraightcross-cutting operations, straight miter-cutting operations,bevel cutting operations, and various combinations of bevel cutting andmiter cutting, commonly called compound cutting operations, with theadjustable fence assembly 20 being adjustable to provide the minimumrequired clearance gap between the fixed and movable fence portions 22and 24, respectively, in any of these cutting modes.

These various cutting operations or working modes, or combinationsthereof, are accomplished by way of a compound pivot mechanism 34,including a pivot arm assembly 21, which is pivotally interconnectedwith the rotatable table assembly 13. The pivot arm assembly 21 includesa pivot mechanism 23 providing for pivotal movement of the saw blade 14into and out of engagement with the workpiece 11, and a pivot mechanism25 providing for pivotal movement of the saw blade 14 among a number ofsquare or bevel cutting configurations. Lateral swinging movement isaccomplished by way of the above-mentioned table assembly 13, which isdisposed for rotation relative to the base assembly 12, thusaccommodating movement among the various cutting configurations.

The pivot arm assembly 21 includes a bifurcated lower and rearward endconfiguration, with this portion of the pivot arm assembly 21 beingsplit to form a pair of pivot legs 29 and 31 with a space therebetweenfor receiving a dust duct 33 therebetween. The dust duct 33 has alongitudinal centerline 33′, and further has a preferablyrectangular-shaped dust-receiving opening 35 at its forward end, atransitional intermediate portion 37, and a preferably circular outletopening 39, to which any of a number of suitable dust-conveying fittings47, or other accessories, can be attached.

As is shown in the end elevation view of FIG. 4, as well asschematically, or diagrammatically, represented in FIGS. 5 through 7,the dust duct 33 pivotally moves with the pivot arm assembly 21 and/orthe rotatable table assembly 13, and thus with the saw blade 14, intoand out of engagement with the workpiece 11 (or even a workpiece 11 a ofdifferent size or shape) in any of the square cross-cutting,bevel-cutting, miter-cutting, or compound miter-cutting operations ofwhich the compound miter saw 10 is capable. However, because the dustduct 33 is fixedly interconnected with the pivot arm assembly 21, itsposition and orientation relative to the saw blade 14 remains constantduring any of these operational modes or configurations, thuscontributing greatly to the consistency and effectiveness of the dustcollection system in the compound miter saw 10, or in other deviceshaving movable work-performing tools.

Preferably, as shown in FIGS. 4 and 5, the constant position andorientation of the dust duct 33 is such that the dust-receiving opening35 is aligned substantially along a line 43 between the dust-receivingopening 35 and the periphery of the saw blade 14, with the line 43extending along a tangent to the rotation of the saw blade 14 at alocation thereon at which the saw blade 14 engages the workpiece 11 (or11 a). In most, if not all, applications of the present invention, theeffectiveness of the dust collection system is maximized when thecompound miter saw 10 (or other work-performing device) is configuredsuch that the line 43 is along a tangent to the rotation of the sawblade 14 (or other cutting tool) at a location 45 at which the saw blade14 (or other cutting tool) exits the workpiece, with such tangentextending to the center of the dust-receiving opening 35, and with suchorientation remaining constant regardless of the position of the movablesaw blade 14 (or other cutting tool).

By way of such an arrangement, the dust duct 33 (and the dust-receivingopening 35) can be much smaller than would otherwise be required of astationary dust collection duct in order to accommodate the widevariance of positions and movement of the saw blade 14 (or other cuttingtool) in a device such as the compound miter saw 10. In addition, in avacuum-powered dust extraction application (such as that discussed belowin connection with FIG. 8, for example), the dust-conveying kineticenergy provided by such a system can be better concentrated in the areato which dust or chips are propelled by the blade or cutting tool. Stillfurther contributing to the effectiveness of the dust collection systemof the present invention is the fact that the position and orientationof the dust duct 33, and thus the dust-receiving opening 35, remainsconstant relative to the saw blade 14 regardless of the movement oradjusted position of either of the blade guard 16 or the fence assembly20. Thus the present invention provides a distinct performance advantageover dust collection ducts or openings attached to, or incorporatedinto, either of these components.

FIGS. 6 and 7 schematically or diagrammatically illustrate a significantfeature of the present invention wherein the orientation of the dustreceiving opening 35 of the dust duct 33 remains constant relative tothe saw blade 14, regardless of the operational configuration in whichthe compound miter saw 10 is used. In FIG. 6, a miter-cutting operationis diagrammatically illustrated, with exemplary miter-cutting positionsof the blade 14, the dust duct 33, and the dust-receiving opening 35being shown in phantom lines and indicated by reference numerals 14 a,33 a, and 35 a, respectively. FIG. 7 similarly diagrammaticallyillustrates exemplary bevel-cutting positions of these components inphantom lines and being indicated by reference numerals 14 b, 33 b, and35 b, respectively. One skilled in the art will readily appreciate thatan exemplary compound cutting operation would involve a combination ofthese two configurations, as well as readily recognizing that theorientation of the dust-receiving opening 35 and the dust duct 33remains constant relative to the saw 14 in any of these configurations,and in both a raised, at-rest position and a work-engaging position (asshown with reference to FIGS. 1 and 4). Furthermore, as is shown inFIGS. 1 through 4, for example, the dust duct 33 is separate andindependent from the blade guard 16 and is therefore not affected byguard movement or adjustment.

In FIG. 8, the dust duct 33 is shown with its outlet opening 39optionally connected, by way of a flexible hose or conduit 51, to anaccessory dust collection receptacle assembly 53. The assembly 53preferably includes a removable collection vessel or bin 57 with aconventional centrifugal separator 59 emptying into the bin 57. As afurther option, the assembly 53 can include a powered vacuum-producingfan or blower device 61, shown schematically in FIG. 8 in phantom lines.With such an optional arrangement, either with or without powered vacuumdust-conveying capabilities, the dust extracted and conveyed away fromthe saw 10 can be contained and collected for convenient disposal. Inlieu of the arrangement shown in FIG. 8, however, a conventional dustcollection bag accessory 63 can also optionally be provided, as shownschematically in FIG. 4, where greater portability is desired.

FIGS. 9 and 10 illustrate an exemplary, generally “funnel-shaped”,configuration for the dust duct 33, with a preferred generallyrectangular cross-section for the dust-receiving opening 35, and withthe transitional intermediate portion 37 converging to a preferredcircular outlet opening 39. As shown in FIGS. 4 and 5, for example, anaccessory dust deflector or diverter 47 can be advantageously added tothe outlet 39, especially when no accessory collector is used. Such ashape or configuration has been found to be highly effective in dustcollection or extraction in experimental prototype versions of thecompound miter saw 10. One skilled in the art will readily recognize,however, that variations or modifications on this configuration,including the adding of accessories as discussed above, may be desirableor required in other types of work-performing devices or applications.

Accordingly, the exemplary compound miter saw 10 constructed inaccordance with the principles of the present invention, includes a dustcollection system that provides for enhanced dust extraction anddiversion away from the operator when performing any of the widelydivergent cutting operations, in any of the various operationalconfigurations, of which the compound miter saw 10 is capable.Furthermore, it provides such increased effectiveness regardless of thesize or shape of the workpiece (within the saw's design parameters) andregardless of the movement or position of the guard or fence. All ofsuch features greatly contribute to the well-being and comfort of theoperator, as well as the cleanliness of the work area.

The foregoing discussion discloses and describes merely exemplaryembodiments of the present invention for purposes of illustration only.One skilled in the art will readily recognize from such discussion, andfrom the accompanying drawings and claims, that various changes,modifications, and variations may be made therein without departing fromthe spirit and scope of the invention as defined in the followingclaims.

What is claimed is:
 1. A compound miter saw comprising: a base; a tablerotatably disposed on said base, said table having a table plane and anaxis of rotation substantially perpendicular to the table plane; a firstfence mounted on said base and having a first highest point from thetable plane; a second fence mounted on said base and having a secondhighest point from the table plane, the first and second fences defininga fence plane and being mounted such that the fence plane is a fixednon-adjustable distance from the axis of rotation of the table; a firstpivot mechanism rotatably connected to the table for rotation about abevel axis, the first pivot mechanism defining a bevel plane, the bevelplane being substantially parallel to and at a fixed non-adjustabledistance from the axis of rotation of the table; a pivot arm pivotallyconnected to a second pivot mechanism, the pivot arm comprising a pairof spaced-apart leg portions and a web connected to the leg portions;said second pivot mechanism connected to the first pivot mechanism, apart of each leg portion being pivotally attached to the second pivotmechanism, the second pivot mechanism mounting the pivot arm formovement about a chopping axis, the chopping axis being lower than atleast one of the first and second highest points; a rotatable cuttingtool mounted on the pivot arm for cutting a workpiece, the cutting tooland pivot arm being pivotable about the chopping axis for selectivechopping movement where the cutting tool moves towards the table inorder to cut the workpiece; and a generally linear dust-receiving ducthaving a longitudinal centerline, an inlet for receiving dust duringperformance of a workpiece cutting operation, and an outlet forexhausting dust during the performance of the cutting operation, whereinthe dust-receiving duct is positioned in the space between the legportions such that the outlet is located at one side of the web,rearward from the inlet located at an opposite side of the web; thedust-receiving duct is oriented relative to the cutting tool so that atangent line of the cutting tool extends into the inlet, the tangentline originating at about a point of intersection between a locus ofpoints formed by the rotation of the periphery of the cutting tool and aportion of the fence plane contained between the first highest point,the second highest point and the table plane, the tangent line and thelongitudinal centerline of the dust-receiving duct being generallycoplanar defining a duct plane that is generally perpendicular to saidchopping axis; and the orientation of the dust-receiving duct remainssubstantially constant relative to the cutting tool during the cuttingoperation.
 2. The saw of claim 1, wherein the dust-receiving duct isfixedly interconnected to the pivot arm.
 3. A compound miter sawcomprising: a base; a table defining a table plane, pivotally mounted tothe base for movement about a miter axis perpendicular to the tableplane for locating the table at a plurality of miter angle settings; afirst fence mounted on one side of the base; a second fence mounted onthe other side of the base, the first and second fences having coplanarsurfaces defining a fence plane, the first and second fences beingmounted such that the fence plane is a fixed non-adjustable distancefrom the miter axis; a rotatable cutting tool; a motor connected to anddriving the cutting tool; a pivot arm comprising a pair of legs and aweb connected between the legs, each leg pivotally mounted to the tableand supporting the cutting tool (1) for pivotal movement about achopping axis to enable the cutting tool to move toward and away fromthe table for cutting a workpiece and (2) for movement about a bevelaxis, and said chopping axis being pivotable about said bevel axis todefine a bevel plane, said bevel plane being substantially parallel toand at a fixed non-adjustable distance from the miter axis of the table;and a generally linear dust-receiving duct having a longitudinalcenterline and being located between the legs, the duct extendingthrough the web and having an inlet on a front side of the web forreceiving dust when cutting the workpiece and an outlet on a rear sideof the web for exhausting the dust; the duct oriented relative to thecutting tool such that during rotation of the cutting tool, a linetangent to the periphery of the cutting tool extends into the inlet ofthe duct, the tangent line originating at about a point formed by theintersection of the periphery of the cutting tool and a region of thefence plane lying between the first and second fence surfaces, thetangent line and the longitudinal centerline of the dust-receiving ductbeing generally coplanar defining a duct plane that is generallyperpendicular to said chopping axis; and the orientation of the ductremaining substantially constant relative to the cutting tool when thecutting tool is pivoted about the chopping axis for cutting theworkpiece.
 4. The saw of claim 3, wherein the dust-receiving duct isfixedly interconnected to the pivot arm.